Intracellular potentials, recorded from the photoreceptors and horizontal cells in the retina of Bufo marinus, exhibited osciallations that were spontaneous and sustained or, in response to brief light stimuli, transient. The frequency of the oscillations (2 -2.5 Hz) was quite stable but varied somewhat from cell to cell and from animal to animal. The frequency of the oscillation was highly dependent upon temperature and background illumination level. The amplitude and duration of the transient oscillations depended upon the stimulus protocol; a very intense full field stimulus was found to be optimum for eliciting large amplitude oscillations which persisted for many cycles. When this protocol was used, both rod and horizontal cell oscillations were initiated only after the cell potential returned to its dark- adapted baseline. The receptive fields of the rod light response and the triggering of the rod transient oscillation were different. Full field (1200 micron diameter) test stimuli elicited the light response and triggered the oscillation while 50 micron diameter stimuli elicited only the light response. Future experiments will be designed to decide between the possibilities that the oscillations arise from horizontal cell or receptor properties, or from interactions between horizontal cells and receptors.